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Review for Physics 8thGrade

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free body diagrams, work, potential and kinetic energy, power, circuits

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Page 1: Review for Physics 8thGrade

Colegio San Patricio

Period Exam IV Practice

Physics

Basic concepts.

1. In physics, work is defined as _____

a. force divided by distance. b. force times distance. c. force times time.

d. force divided by time. e. distance divided by time.

2. The unit of work is the _____

a. joule. b. second. c. watt. d. newton. e. meter.

3. Potential energy is the energy an object has because of its ____

a. temperature. b. density. c. speed. d. size. e. location.

4. An object that has kinetic energy must be ____

a. at rest. b. moving. c. smiling. d. elevated

5. Power is defined as the ____

a. work done times the time taken to do that work.

b. work done on an object divided by the time taken to do the work.

c. force on an object times the distance the object moves.

d. force on an object divided by the time the force acts.

e. distance divided by the time taken to move that distance.

6. The unit of power is the ____

a. second. b. newton. c. watt. d. joule. e. meter.

7. Total mechanical energy is defined as ____

a. kinetic energy. b. potential energy. c. sum of PE and KE. d. divide PE into KE.

Problem Solving.

8. A student lifts a bucket with a 98 N force out of a well. If the bucket is lifted 30 m

How much work was done?

9. A child pulls a wagon with a force of 20 N. The wagon moves 6 meters during

the 5 seconds that the child is pulling it. Find the power.

Page 2: Review for Physics 8thGrade

page 2

10. Calculate the following:

a. The potential energy at points A.

b. The potential energy at point B.

11. A 10kg object moves at 1 m/s. Find the kinetic energy of the object.

12. Suppose a moving car has 2000 J of kinetic energy. If the car's speed doubles,

how much kinetic energy would it then have?

a. 6000 J b. 2000 J c. 1000 J d. 8000 J e. 4000 J

13. Using these electronic components construct an electric circuit like the one you

used for your project.

page 3

20 m

12 m

A

B

C

Introduction to Circuit Diagrams 3

Basic Electronic ComponentsBulb Switch

Battery

L.E.D. Resistor

Buzzer

Motor

DiodeCapacitor

m = 20kg

Page 3: Review for Physics 8thGrade

14. Draw a free body diagram for each picture including all forces acting.

A lamp resting on the night stand.

A dog running at the park.

15. Identify each simple machine.

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